Gate operating mechanism for conveying buckets



July 28, 1970 G. R. HEAL 3,521,925

GATE OPERATING MECHANISM FOR CONVEYING BUCKETS Filed June 24, 1968 United States Patent 3,521,925 GATE OPERATING MECHANISM FOR CONVEYING BUCKETS Gerald R. Heal, Scarborough, Ontario, Canada, assignor to Dominion Magnesium Limited, Toronto, Ontario, Canada Filed June 24, 1968, Ser. No. 739,350

Int. Cl. B66c 3/00 US. Cl. 29471 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention The invention is in the general field of buckets for conveying concrete and the like in the building industry and more particularly in the field of gate operating mechanism for such buckets.

Description of the prior art In the construction industry, buckets as used for conveying concrete and the like are usually suspended from a cable on the boom of an operating crane. The bucket has bottom opening and closing gate sections which are manually operated by means of a gate operating mechanism which frequently includes linkage or gear systems to provide complementary movement of the gate sections, as well as return spring means.

SUMMARY OF THE INVENTION The present invention seeks to provide a gate operating mechanism for a bucket wherein the arrangement of the moving parts and spring means is such that actuation of the parts is under low inertia and, therefore, under substantially constant control of the operator during opening and closing movements of the gates.

The invention relates to a bucket having a bottom discharge opening, a pair of gate sections each comprising a closure plate and a pair of arms carrying the plate, and a pivot pin from which the arms and plate are suspended, the gate sections being swingable about the axes of the pins toopen and close the opening. A second arm is fixedly mounted on each suspension arm of a first gate section and a projection is provided on the other gate section in radially opposite relation to the closure plate thereof. A link pivotally connects the second arm and the projection. A spring connects the arm of the first section at a point intermediate its pivot pin and closure plate to the pivot pin of the other section. An operating handle is fixed to the suspension arms of the first section.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of a bucket incorporating the structure of the present invention, in closed position,

FIG. 2 is a side elevation of the bucket in open position, and

FIG. 3 is a plan view, partly in section.

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DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, the bucket shown is of generally conventional form and comprises a main body 10, usually referred to as the cone, and a conical section 11 at the base of the main cone leading to an open-ended discharge box 12 having a discharge opening 13.

Discharge from box 12 is controlled by a gate 14 which may be operated to open or close or partially open the box.

Gate 14 comprises a pair of closure sections 15 and 16 each comprising a plate 17 swingably mounted on the bucket by means of a pair of triangular arms 18 each pivotally carried on a pin 19 mounted on conical section 11. As shown, each plate is curved about the radius of its pivotal movement and, in closed position, lies in the plane of the corresponding lower edge 20 of the discharge box. The plates 17 are substantially coextensive in size and together in closed position form a complete closure of the opening 13 (FIG. 1). Reinforcing ribs 21 may be provided on the external surface of each plate.

Preferably, the bucket and gate are formed of magnesium alloy for lightness of weight combined with adequate strength in operation.

Gate operating mechanism comprises an arm 22 pivotally mounted adjacent one end on each pin 19 of each section 15 and 16 but having its other end fixed by pin 23 to arm 18 of the section. Thus, each arm 22 swings with arm 18 as it pivots about pin 19.

As shown in FIG. 1, in the closed position of the gate, the arms 22 of each pair are inclined towards each other with their fixed ends in engagement, while in the open position of FIG. 2, the arms 22 are in spaced, parallel and vertically disposed relation.

A link 24 pivotally connects each pin 23 of section 15 with a pin 25 mounted in a projection 26 fixed to arm 18 of section 16. Projection 26 and pin 25 are substantially radially opposite the main portion of the corresponding arm 18.

An operating handle comprises a U-shaped rod 27 fixed by means of bracket '28 to a lower portion of each arm 18 of section 15.

A coil spring 29 has one end connected to gate section 15 at each handle bracket 28 and its other end connected to the other gate section 16 at pivot pin 19. The axes of springs 29 are thus inclined downwardly from the horizontal in both the closed and open positions of the gate. Each spring is tensioned by movement along an arc of one gate section relative to the pivot of the other so that a minor tension is exerted in the fully open position when the gravity effect to close the gates is at a maximum and maximum spring tension is exerted when the gates are closed.

The effective radius of each arm 22 is equal to that of projection 26. Thus, the linkage described gives immediate and equal opening of both gate sections With equal travel so that both sections reach open position at the same moment.

The structure described permits effective and convenient operation. No offset loading or side thrust is imposed on the links or bearings. There is a high initial thrust on opening the gate because pressure on the handle transmitted along its length starts the gate opening before any conscious effort is made to apply a turning movement. This provides immediate control which is not possible when a high static load has to be overcome at the start which may lead to a runaway opening once movement has started. Such control is especially important in detail work where small known amounts of concrete must be spotted in exact locations. The accuracy required is aided by the fact that the spring ten- 3 sion, as previously indicated, is at a maximum in the closed position, resulting in a clean cut-01f with a bucket still containing a heavy load.

It is also important, when the gates are fully opened, to dump the entire load, since it gives the operator considerable control over the reaction elfects of the sudden release of load from the suspending (and stretched) cable and the elastically strained crane-boom, which can be great enough to cause an uncontrollably emptied bucket to spring several feet into the air.

Use of magnesium alloy allows considerable freedom of design, so that all parts are extremely robust and bearing areas are large without adding to the total weight while retaining the easy movement of the system because of lightness of the components since the moving parts are of low inertia.

The presently described structure avoids the use of gears in which small stones may cause wear and jamming.

Return springs as heretofore employed increase in tension in proportion to the opening movement of the gate so that the minimum eifect is reached when the gate is approaching closure. As a result, leakage may occur from slack gates, or if a stronger spring is used, the force required on the handle is so great that any control is lost.

I claim:

1. In a bucket having a bottom discharge opening, first and second gate sections each comprising a closure plate, an arm fixed to each end of said plate, and a pivot pin from which each said arm and plate are suspended, said sections being swingable about the axes of said pins to open and close said opening, gate operating mechanism comprising a second arm mounted on each said pivot pin of each said first arm and swingable therewith, said second arms at each end of said plate being inclined towards said opening and being engageable in the closed position of said sections, a projection on each said first arm of said second section in radially opposite relation to said closure plate thereof, a link pivotally connecting each said second arm and said projection, a spring connecting each said first arm of said first section at a point intermediate said pivot pin and said closure plate thereof to said pivot pin of the adjacent one of said first arms of said second section, and a handle fixed to said first arms of said first section.

2. Gate operating mechanism as defined in claim 1, said second arms and said projection being of substantially equal length.

3. Gate operating mechanism as defined in claim 1, said gate sections having a fully closed position and a fully open position, the adjacent ones of said second arms being inclined towards each other and in substantial engagement in said closed position and in substantially parallel relation to each other in said open position.

4. Gate operating mechanism as defined in claim 1, said bucket and said gate sections being formed of magnesium alloy.

References Cited UNITED STATES PATENTS 10/1911 Doud 29471 3/1957 Nave 222503 US. Cl. X.R. 105290 

